Portable communication devices such as mobile telephones and personal digital assistants (PDAs) generally have limited computational resources in terms of one or more factors such as memory, processing power, communication bandwidth and network connection time. Such devices are therefore referred to herein as “lightweight” devices. Although lightweight devices are increasingly being used for applications such as sending and retrieving information over the Internet, their limited resources can become problematic for many important applications, particularly those involving secure communications implemented using cryptography. For example, the computational requirements associated with many well-known digital signature protocols can prevent their effective implementation in lightweight devices.
An example of an application that can benefit from the use of cryptographic techniques is on-line gaming implemented over the Internet or a wireless network. More particularly, there is a danger in such an application that an on-line casino or other provider of the gaming service may skew the probabilities of winning in their favor, in a manner which is not readily detectable by the users. Although this problem also exists for “real-world” casinos, it is considerably aggravated in the Internet and wireless network settings, at least in part because the on-line providers may be located in foreign jurisdictions and in any case can easily change their physical location in the event that trouble arises. The honesty of real-world casinos can generally only be verified using auditing methods. However, cryptographic techniques could be used to provide accountability in the on-line gaming context. Unfortunately, existing cryptographic techniques of a type likely to be useful in this context generally involve substantial computational overhead and as a result are not appropriate for implementation using mobile telephones and other lightweight devices.
It is therefore apparent that a need exists in the art for improved cryptographic techniques, suitable for use in secure mobile gaming and other applications, and implementable in lightweight devices.